- replaced bitwise &= on bools, with explicit && to make KW happy

- replace "unsafe" memcpy with "safe" :) std::copy_n to make KW happy

G-API: Zero-height mat is cause of crash

* Added check for zero-height Mat case

* Refactoring, added validate_input_arg func

* No bool function now

* Add Tengine support .

* Modify printf to CV_LOG_WARNING

* a few minor fixes in the code

* Renew Tengine version

* Add header file for CV_LOG_WARNING

* Add #ifdef HAVE_TENGINE in tengine_graph_convolution.cpp

* remove trailing whitespace

* Remove trailing whitespace

* Modify for compile problem

* Modify some code style error

* remove whitespace

* Move some code style problem

* test

* add ios limit and build problem

* Modified as alalek suggested

* Add cmake 2.8 support

* modify cmake 3.5.1 problem

* test and set BUILD_ANDROID_PROJECTS OFF

* remove some compile error

* remove some extra code in tengine

* close test.

* Test again

* disable android.

* delete ndk version judgement

* Remove setenv() call . and add License information

* Set tengine default OFF. Close test .
Co-authored-by: Vadim Pisarevsky <vadim.pisarevsky@gmail.com>

Image sharpness, as well as brightness, are a critical parameter for
accuracte camera calibration. For accessing these parameters for
filtering out problematic calibraiton images, this method calculates
edge profiles by traveling from black to white chessboard cell centers.
Based on this, the number of pixels is calculated required to transit
from black to white. This width of the transition area is a good
indication of how sharp the chessboard is imaged and should be below
~3.0 pixels.

Based on this also motion blur can be detectd by comparing sharpness in
vertical and horizontal direction. All unsharp images should be excluded
from calibration as they will corrupt the calibration result. The same
is true for overexposued images due to a none-linear sensor response.
This can be detected by looking at the average cell brightness of the
detected chessboard.

* core(test): FP16 norm test

* core: norm()-FP16 disable OpenCL

* core(norm): fix 16f32f local buffer size

Added checklist and recommendations to issue template

ToT libc++ (LLVM) no longer includes <sstream>
as part of <complex> which breaks building opencv.
Include <sstream> header explcitly to fix this.

* core(logger): add CV_LOG_ONCE_xxx() CV_LOG_IF_xxx() macros

* core(logger): keep tests disabled

* imgproc(integral): avoid OOB access

* imgproc(test): fix integral perf check

- FP32 computation is not accurate

* imgproc(integral): tune loop limits

clGetSupportedImageFormats returns CL_INVALID_VALUE if called with
num_entries 0 and a non-NULL image_formats pointer so let's not do that.

Use argument value for 'mat' in call to format for vector_mat and vector_mat_template

* Supported Div op for constants

* Added Mul test

The hard-coded string value "Mat" was used in the two format strings for vector_mat and vector_mat_template, preventing UMat arguments to functions that have these types from working correctly. as noted in #12231.